Audio signals corresponding to a picture such as a movie are recorded on multiple channels so that the recorded audio signals are reproduced from speakers disposed at a left front position, a right front position, a center front position, a left back position, and a right back position of the listener or from speakers disposed at a left position and a right position of the listener. With these speakers, the position of a sound source in a picture matches the position of a real sound image. Thus, a sound field with a naturally spacial impression is accomplished.
However, when the listener listens to such sound with headsets, the sound image is localized in his or her head. Thus, the direction of the picture does not match the localized position of the sound image. Consequently, an unnatural sound image is localized. In addition, the audio signals of individual channels cannot be reproduced in such a manner that the localized positions thereof are separated. This problem also takes place when the listener listens to only sounds of multiple channels such as musical sounds. In this case, unlike with sounds reproduced with speakers, the listener hears sounds from his or her head. Thus, since the localized positions of sound images are not separated, a sound field is very unnaturally reproduced.
An object of the present invention is to solve unnaturalness in sounds reproduced with headsets, in particularly, to localize a sound image at a predetermined position.